Development of MR methods that can detect early changes of cartilage degeneration are important in preventing the progression of osteoarthritis. Conventional MR methods are not adequate for early detection of changes in cartilage. It is suggested that the early stages of osteoarthritis are accompanied by loss of proteoglycans, increase in water content and changes in water relaxation times. In order to investigate whether T1r (spin lattice relaxation in rotating frame) imaging provides better contrast in cartilage, we have performed T1r imaging of articular cartilage with and without applied pressure. The experiments have been carried out on bovine articular cartilage plugs. Spin echo images with fixed TE and varying lengths of spin locking pulse have been obtained. T1r images were constructed by fitting the intensities of individual pixels in each image to the T1r expression using a two parameter least squares method. T1r -weighted images are brighter compared to T2-weighted images with equal TE. There is a distribution of T1r values across cartilage tissue which increases with applied pressure. Degeneration of cartilage, which is associated with longer T2 values, is expected to change the contrast in T1r-weighted images. We found that global T1r values varied from 60 ms to 120 ms over a spin-locking frequency range of 50Hz-4kHz. Optimization of spin locking field strength and implementation of off-resonance T1r imaging studies on osteoarthritic cartilage, are in progress.